Very stylish, especially together with the music. You really captured that sci-fi feel with the models. The intro screen was also pretty funny.
Would've loved to see more enemies, but it sounds like you're working on that. Also, would be cool if you added something for the type of people who collect all the coins / do the valve thing (although I guess it may be overkill for an alpha demo).
Didn't notice any noteworthy bugs or quality issues, it got a little frame-droppy on the outside platform when basically the whole level was visible, but I guess that's to be expected.